Sewing machine



March 17, 1964 H. E. REDMAN SEWING MACHINE Filed Nov. 1, 1962 UnitedStates Patent 3,125,049 EWING MACHINE Howard E. Redman, Weymouth, Mass.,assignor to United Mattress Machinery Co., Inc., Quincy, Mass., acorporation of Maine Filed Nov. 1, 1962, Ser. No. 234,782 3 Claims. (Cl.112-184) The present invention relates to improvements in a lock-stitchsewing machine having a pointed thread carrying needle and a rotaryhook.

Theinvention is herein disclosed as embodied in a mattress quilt sewingmachine of the general type in which a mattress quilt supporting frameis mounted on a carriage assembly for movement with relation to thesewing mechanism for eifecting the feed of the stitching operation overthe face of the mattress quilt in any desired direction.

The sewing mechanism comprises an overarm in which is carried a presserfoot and a vertically reciprocating thread carrying needle, and anunderarm beneath the work in which is housed a rotary looper mechanismincluding a rotary hook and a bobbin case loosely supported againstrotation of the hook. In mattress quilt sewing machines of the typedescribed, considerable difficulty has been encountered in maintaining aclose co operation of the needle and rotary hook because of the heavylateral stresses imposed on the needle shank by the feeding movements ofthe mattress quilt which may be in any direction in accordance with thedictation of the pattern.

Objects of the present invention are to provide a novel and improvedconstruction of the devices for supporting and guiding the needle androtary hook mechanism of the machine which will provide for the moreeffective support of the needle when extended through the work incooperative relation with the rotary hook and for the more 'efiicientoperation of the ortary hook mechanism including the bobbin casingduring the loop taking and stitch take-up operations.

In accordance with the invention, the sewing mechanism comprises anoverarm in which is supported a vertically reciprocating straight threadcarrying needle and an underarm in which is housed a rotary hooksupported to turn about a vertical axis, and supporting and guidingdevices for the needle and rotary hook mechanism which are rigidlymounted on said underarm to provide an accurate and dependablecooperation of the needle with the rotary hook. The construction andarrangement of the needle guiding devices is such that the needle ispositioned positively and accurately with relation to the rotating hookregardless of the direction of feed of the work to insure the accurateand unimpeded forming of the successive stitches by the operation ofsaid devices.

Further in accordance with the invention the supporting and guidingdevices insuring the desired cooperation of the straight thread carryingneedle and rotary hook include a relatively fixed nylon insert whichacts as each successive loop is drawn in during the retracting movementof the needle to absorb the repeated knocking of the bobbin casingagainst the nylon insert to maintain the casing at all times in adesired angular relation.

With the above and other objects in view as may hereinafter appear theseveral features of the invention consist in the devices, combinationsand arrangement of parts hereinafter described and claimed together withthe advantages to be obtained thereby which will be readily understoodby one skilled in the art from the following description taken inconnection with the accompanying drawings, in which:

FIG. 1 is a sectional view inside elevation of a por- 3,125,049 PatentedMar. 17, 1964 "ice tion of a sewing machine embodying the severalfeatures of the invention;

FIG. 2 is a detail plan view taken on a line 22 of FIG. 1 showing theneedle, throat plate and rotary hook assembly including the rotary hookand bobbin case mounted therein;

FIG. 3 is a detail sectional view in side elevation taken on a line 3-3of FIG. 2 but on an enlarged scale to illustrate particularly therelation of the throat plate, needle guide, and rotary hook assemblyincluding the bobbin case;

FIG. 4 is a detail sectional plan view taken on a line 44 of FIG. 3 toillustrate partly the lower rigidly supported needle guide foraccurately positioning the needle with relation to the rotary hook;

FIG. 5 is a sectional view in side elevation taken on a line 55 of FIG.3 illustrating particularly the relationship of the needle guide and thethroat plate including the resilient fiber insert for supporting thebobbin casing from oscillation during the formation of successivestitches; and

FIG. 6 is a somewhat fragmentary view similar to FIG. 3 showing theneedle in two successive positions during the retracting loop drawingstroke.

The sewing mechanism illustrated in the drawings as embodying in apreferred form the several features of the invention is shown as appliedto a machine of the general type having a mattress quilt supportingframe, and a carriage assembly on which the frame and quilt supportedthereby are mounted for movement in a plurality of directions for thetransfer of the stitching operation over the face of a mattress quilt inaccordance with a pattern.

Inasmuch as the mechanism for supporting and feeding the supportedmattress quilt is well known in the art and forms specifically no partof the present invention, no further description and illustrationthereof is believed necessary.

Referring more specifically to the drawings, the mattress quilt sewingmachine illustrated as embodying in a preferred form the severalfeatures of the invention comprises an overarm 20 in which is carried apresser foot 22 and a vertically reciprocating thread carrying needle24. The machine is provided also with an under arm 26 which extendsbeneath the supported mattress quilt and has mounted therein a rotaryhook assembly in cluding a rotary hook 28, a bobbin case 30 and a bobbin32 supported therein. A removable cover or throat plate 33 attached tothe underarm 26 provides an easy access to the rotary hook mechanism,and also as hereinafter set forth provides a means for holding thebobbin case in position, and for guiding the needle as it is drivendownwardly through the work to the hook engaging position.

The rotary hook 28, as shown in FIG. 1, is mounted to rotatehorizontally about a vertical axis and is mounted for this purpose upona vertical shaft 34 which is continuously driven from a horizontal driveshaft 36 through bevel gears 38, 40 secured respectively to the shafts36 and 34.

The rotary hook 28 comprises generally an annulus which has formedtherein the hook 42 and is rigidly secured to a base member 44 having adownwardly projecting sleeve socket which is fitted upon and attached tothe vertical shaft 34 by means of a pin 46.

The bobbin case 30 and bobbin 32 are loosely supported within the rotaryhook element and rest upon two roundheaded buttons forming part of thehook assembly, not shown, to permit a loop of thread to be passedreadily around the bobbin passing between the case and the hook assemblyincluding the hook member and base member 44. For holding the bobbincase against rotation a projection 50 is formed on the upper face of thebobbin case and is arranged for engagement between two abutting surfaces52 and 54 formed on the underside of the throat plate 33 secured to theunderarm 26. As hereinafter more fully pointed out in connection withthe operation of the device, a nylon insert 58 is supported in a recessformed in the abutment 52 of the throat plate 33 to provide anon-wearing cushion against the repeated knocking of the bobbin caseagainst the abutment 52 which takes place during the formation of eachsuccessive stitch. The bobbin case in turn provides support for thebobbin 32 which is mounted on a central pin 69 formed in the bobbin caseand is held in position by a tiltable pin locking device 62 of ordinarydescription.

The needle 24 is formed with an eye 64 through which the needle threadpasses, a longitudinally extending groove 66 along which the thread isled from supply to the needle eye, and a fiat face 68 on the oppositeside of the needle shank through which the transversely moving rotaryhook is passed to engage a portion of the thread extending upwardlyalong said flat face 68 from the needle eye 64 to the work.

With the present construction an improved needle guiding device isprovided to accurately locate the downwardly extended needle withrelation to the rotating hook 28 and thus to insure proper engagement ofthe thread by the hook. During the downward movement of the needle, thepointed end thereof passes first through a bushing 70 mounted in thethroat plate 33, said bushing being formed with a rounded inner top edgeto engage and guide the needle point through the bushing. Immediatelybelow and separated from the bushing 76 there is provided a needle guide72 consisting of a block in which is formed a vertically extending bore74 having an internal diameter slightly greater than the needle 24 sothat the needle will be accurately positioned therein with relation tothe rotating hook.

The needle guide 72 extends downwardly from an upper level slightlybelow the underside of the throat plate 33 to a lower level which isnear the bobbin 32. A rotary hook receiving cutout 76 is formed in thatside of the guide adjacent the rotary hook with the rear face thereoflying in a vertical plane passing through the bore 74 and a forwardlysloping upper face at a level which permits free movement of the rotaryhook therebeneath. The needle guide 72 is also formed with a verticallyextending slot 78 which opens into the rotary hook facing side of theneedle guide 72 and provides passage for the needle thread looped aboutthe rotary hook assembly including the bobbin casing particularly duringthe retracting movement of the needle. The needle guide 72 is thusprovided with an upper portion which substantially encloses the shank ofthe downwardly moving needle providing a firm support for the needleagainst displacement in any direction regardless of the direction offeed, and an additional lower portion which provides support for thoseportions of the needle shank opposite and away from the rotary hook,while free passage is permitted for the rotary hook transversely acrossthe flat face 68 of the needle to receive a loop of the needle thread.

The bobbin thread extends from the bobbin upwardly through an outlet 80in the bobbin casing above the thread guide 74 through the bushing 70 tothe work.

The guiding and supporting devices above described coperate with theneedle and rotary hook assembly during each stitch forming cycle in thefollowing manner:

The pointed thread carrying needle during its downward stroke throughthe work first engages and is guided through the bushing 70 which asshown in the drawing has an aperture of substantially larger diameterthan that of the needle and a rounded top surface which will engage withand move the needle, even though it is substantially deflected by thework feed, back into its vertically aligned position. The pointed end ofthe needle now enters the upper end of the bore 74 formed in the needleguide 72 which accurately positions and supports the needle along itsvertical axis against stresses which may be applied in any direction bythe continuous feeding movements imparted to the work. As previouslynoted the bore 74 is completely walled-in at its upper end except forthe narrow slot 78 so that the needle is accurately supported and heldin position with relation to the rotary hook regardless of the directionof feed and consequent tendency of the needle to be deflected in acorresponding direction.

The arrangement and shaping of the needle guide 72 with relation to thebushing 70 and the rotary hook assembly is well adapted also to insure amaximum of certainty and efliciency in the handling of the needle andbobbin thread.

A slight upward movement of the needle from its extreme low positioncauses a loop of the needle thread to be thrown out into the path of theshuttle which passes through the cutout 7 6 in the needle guide 72closely adjacent the flat face 68 of the needle to engage with and passthe said loop around the bobbin casing. Continued upward movement of theneedle causes the two legs of the needle loop thus formed to be drawnupwardly through the slot 78 as best shown in FIG. 6. During continuedmovement of the needle to its high position, the two legs of the needleloop are drawn upwardly through the bushing 70 and through the work, notshown, causing a bight of the bobbin thread to be drawn firmly againstthe underside of the work to form the next succeeding stitch.

The rotary movement of the rotary hook and the subsequent drawing in ofthe loop during the retracting movement of the needle causes the bobbincasing to be biased sharply against the nylon insert 58 which acts as abuffer to hold the rotary casing in position against rotation with therotary hook. The use of the nylon insert 58 has the advantage that noappreciable wear takes place between the adjacent surface of the bobbincasing and the nylon buffer even after an extended period of use. Noiseis substantially reduced. The nylon surface also has the advantage thatit provides a highly polished, smooth surface past which the loop ofthread taken by the looper is drawn with a minimum of friction andresistance.

The invention having been described, what is claimed 1. In a sewingmachine having a reciprocating straight needle at one side of the workand a rotary hook assembly at the other side of the work comprising arotary hook disposed to rotate continuously in one direction about anaxis parallel to the needle, and a bobbin case mounted within the hook,the combination of work supporting means including a base, a throatplate mounted in the base having an aperture of a diameter providing aloose fit with the needle to loosely engage and guide the needle belowthe work level, and a needle guide fixedly supported on said basebeneath and separated from said throat plate at one side of the rotaryhook shaped to provide a needle receiving bore cylindrically walled-inat its upper end, with a narrow vertical thread receiving slot facingthe hook of less width than the diameter of the needle and larger thanthe diameter of the yarn and opening into said bore through saidwalled-in portion of the bore, and a rotary hook receiving cutoutextending across the rotary hook side of said guide toward the lower endof said bore with the rear face of said cutout lying in a vertical planepassing through said bore, and a forwardly sloping upper portion of saidcutout providing surfaces for guiding the needle thread drawn about therotary hook assembly upwardly through said slot and through the needleeye during the retracting movement of the needle.

2. In a sewing machine having a sewing mechanism including areciprocating straight needle at one side of the work and a rotary hookassembly at the other side of the work comprising a rotary hook disposedto rotate continuously in one direction about an axis parallel to theneedle, and a bobbin case mounted within the hook, and WOIK pportingmeans including a base, the combination of supporting and guidingdevices for said sewing mechanism including a throat plate mounted onsaid base having formed thereon two abutments separated and facing inopposite directions from one another circumferentially of said rotaryhook axis, said bobbin case being formed with faces opposing saidabutments, and an insert of a resilient plastic material located betweenthe one of said abutments and opposed face of said bobbin case to arrestrotation of said bobbin case in the direction of rotation of said rotaryhook.

3. In a sewing machine having a reciprocating straight needle at oneside of the work and a rotary hook assembly at the other side of thework comprising a rotary hook disposed to rotate continuously in onedirection about an axis parallel to the needle, and a bobbin casemounted within the hook, the combination of work sup porting meansincluding a base, a throat plate mounted in the base having a bushing toloosely engage and guide the needle below the work lever, and a needleguide fixedly supported on said base beneath and separated from saidthroat plate at one side of the rotary hook shaped to provide a needlereceiving bore cylindrically walled-in at its upper end, with a narrowvertical thread receiving slot opening into said bore through saidwalled-in portion from the side of said guide adjacent the rotary hook,and a rotary hook receiving cutout extending across the rotary hook sideof said guide toward the lower end of said bore with the rear face ofsaid cutout lying in a vertical plane passing through said bore, and aforwardly sloping upper portion of said cutout providing surfaces forguiding the needle thread drawn about the rotary hook assembly upwardlythrough said slot and through the needle eye during the retractingmovement of the needle, said throat plate being formed with twoabutments separated from and facing one another circumferentially ofsaid rotary hook axis, said bobbin case being formed with faces opposingsaid abutments, and in insert formed of a resilient plastic materialbeing provided between one of said abutments and with the opposed faceof said bobbin case to arrest rotation of said bobbin case in thedirection of rotation of said rotary hook.

References Cited in the file of this patent UNITED STATES PATENTS983,343 Bayer Feb. 7, 1911 1,162,987 De Voe Dec. 7, 1915 1,413,274 HoratApr. 18, 1922 1,775,913 Parkes Sept. 16, 1930

1. IN A SEWING MACHINE HAVING A RECIPROCATING STRAIGHT NEEDLE AT ONESIDE OF THE WORK AND A ROTARY HOOK ASSEMBLY AT THE OTHER SIDE OF THEWORK COMPRISING A ROTARY HOOK DISPOSED TO ROTATE CONTINUOUSLY IN ONEDIRECTION ABOUT AN AXIS PARALLEL TO THE NEEDLE, AND A BOBBIN CASEMOUNTED WITHIN THE HOOK, THE COMBINATION OF WORK SUPPORTING MEANSINCLUDING A BASE, A THROAT PLATE MOUNTED IN THE BASE HAVING AN APERTUREOF A DIAMETER PROVIDING A LOOSE FIT WITH THE NEEDLE TO LOOSELY ENGAGEAND GUIDE THE NEEDLE BELOW THE WORK LEVEL, AND A NEEDLE GUIDE FIXEDLYSUPPORTED ON SAID BASE BENEATH AND SEPARATED FROM SAID THROAT PLATE ATONE SIDE OF THE ROTARY HOOK SHAPED TO PROVIDE A NEEDLE RECEIVING BORECYLINDRICALLY WALLED-IN AT ITS UPPER END, WITH A NARROW VERTICAL THREADRECEIVING SLOT FACING THE HOOK OF LESS WIDTH THAN THE DIAMETER OF THENEEDLE AND LARGER THAN THE DIAMETER OF THE YARN AND OPENING INTO SAIDBORE THROUGH SAID WALLED-IN PORTION OF THE BORE, AND A ROTARY HOOKRECEIVING CUTOUT EXTENDING ACROSS THE ROTARY HOOK SIDE OF SAID GUIDETOWARD THE LOWER END OF SAID BORE WITH THE REAR FACE OF SAID CUTOUTLYING IN A VERTICAL PLANE PASSING THROUGH SAID BORE, AND A FORWARDLYSLOPING UPPER PORTION OF SAID CUTOUT PROVIDING SURFACES FOR GUIDING THENEEDLE THREAD DRAWN ABOUT THE ROTARY HOOK ASSEMBLY UPWARDLY THROUGH SAIDSLOT AND THROUGH THE NEEDLE EYE DURING THE RETRACTING MOVEMENT OF THENEEDLE.